JP3257079B2 - Application method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating method, and more particularly to a coating method for applying a magnetic paint when manufacturing a magnetic recording medium.

[0002]

2. Description of the Related Art Conventionally, as a device for applying a magnetic paint when manufacturing a coating type magnetic recording medium, a coating device using a roll such as a gravure roll or a reverse roll has been mainly used, and particularly, a wide range of structural viscosity is applied. In general, a direct gravure method capable of applying the above-mentioned method is used.

[0003] The gravure roll is subjected to a surface treatment such as hard chrome treatment in consideration of wear resistance. Depending on the structural viscosity of the magnetic paint, the transferability of the paint from the roll onto the base film, which is a non-magnetic support, is impaired, and the output tends to fluctuate due to uneven coating thickness and drop out due to paint scattering. These problems tend to become more pronounced as the coating speed increases.

In particular, when a magnetic paint having a high structural viscosity (thixotropic property) or a metal-based magnetic paint is transferred onto a nonmagnetic support having a thickness of 50 μm or more (eg, a floppy disk).
However, there is a problem that an air layer is easily formed between the cell groove of the gravure roll and the non-magnetic support, and a transfer failure occurs.

On the other hand, as a new coating apparatus capable of solving such a problem, an extrusion (die) type coating apparatus has attracted attention and has already been partially used. This extrusion type coating apparatus has a wide slit facing the front end face, and is provided with a die in which the vicinity of the front end is made into a doctor edge, and is directed toward the surface of the running non-magnetic support. Then, the magnetic paint continuously extruded is applied on the non-magnetic support with a uniform thickness by the doctor edge.

[0006] Such an extrusion type coating apparatus can easily form a coating film having a uniform film thickness, and can reduce the cost and size of the apparatus because a roll having a large diameter is not used. And has been used in the fields of photographic film and photographic paper.

In the extrusion-type coating apparatus, an orifice-shaped paint reservoir having a length substantially equal to the width of the slit is provided on the back side of the slit provided at the tip of the die. A paint made of a magnetic material is supplied into the paint reservoir called a pocket. Then, the paint is extruded from the pocket into the slit with a predetermined pressure,
A constant amount of paint is stably supplied to the surface of the non-magnetic support from the tip of the slit.

However, when the paint is extruded from the tip of the slit to the surface of the non-magnetic support, the extruded paint is applied to the back surface of the non-magnetic support at both ends in the width direction of the non-magnetic support. It may go to the side. For this reason, the coating material wrapped around adheres to the surface of the traveling roll supporting and moving the non-magnetic support from the back side, and the traveling roll is contaminated, or the magnetic recording obtained after drying of the coating film. A problem arises in that both ends in the width direction of the medium are swollen and a shape defect occurs.

In order to solve this problem, the width of the slit is substantially reduced by interposing spacers at both ends in the width direction of the slit, and the area where the paint is supplied from the slit to the surface of the non-magnetic support is reduced. Regulatory methods are in place. According to this method, an uncoated portion (a portion to which the paint is not applied) having a width of about 3 to 10 mm can be formed at both ends in the width direction of the nonmagnetic support. It is possible to prevent the paint from flowing around the back side.

However, when the coating is performed so that the uncoated portion is formed on the non-magnetic support as described above, as shown in FIG. The front end surface 25 of 24 comes into direct contact. As a material of the die 24, generally, a sintered alloy (a cemented carbide) such as stainless steel or steel, a high-speed steel, or a carbon tool steel is used, and its surface is mirror-finished. As described above, when the non-magnetic support 21 is continuously driven in a state of being in direct contact with the die 24, the surface of the uncoated portion 22 is shaved by friction with the die 24, and Dust 2 on the contact surface of
6 or scratches on the tip surface 9 due to wear. When the dust 26 is generated or the tip end surface 9 is damaged, the adhesion of the coating film 23 to the non-magnetic support 21 and the slit accuracy are reduced, and the quality characteristics of the obtained magnetic recording medium are reduced. Has a major adverse effect.

[0011]

SUMMARY OF THE INVENTION Accordingly, the present invention has been proposed in view of the above-mentioned conventional circumstances, and a coating apparatus and a coating apparatus using a gravure roll, in which the magnetic paint is likely to transfer and does not cause coating unevenness. The aim is to provide a method. Another object of the present invention is to provide an extrusion-type coating apparatus that can prevent adverse effects caused by contact between the tip surface of a die and the surface of a support.

[0012]

According to a first aspect of the present invention, there is provided a coating method for continuously transferring and coating a magnetic coating material supplied to the surface of a gravure roll onto a support in order to achieve the above object. In the above gravure roll surface is subjected to a low friction treatment by electroless nickel plating coating or composite plating coating in which electrolytic tetrafluoroethylene fine particles are dispersed in an electrolytic nickel-phosphorus coating, the viscosity by a B-type viscometer is 5,000 to It is characterized in that a magnetic paint of 10,000 cps is applied by a gravure roll that has been subjected to the low friction treatment.

[0013]

In the above-mentioned coating apparatus, the coating is picked up by a gravure roll having a cell pattern engraved on its surface, adhered to a support, and pressed by a backup roll to perform coating. Since the surface of the gravure roll has been subjected to a friction reduction treatment, it has excellent transferability even when using a high-viscosity paint as described above, and stably coats without causing coating unevenness on the support. Can be formed.

As the friction reduction treatment, surface treatment using a composite plating film containing fine particles having lubricity is suitable. For example, fine particles of ethylene tetrafluoride (trade name, Teflon) are dispersed in an electroless nickel film. And those obtained by dispersing fine particles of ethylene tetrafluoride in an electrolytic nickel film. The composite plating film is preferably formed so that the contact angle with respect to water is about 45 °. If the contact angle is small, transferability to a non-magnetic support is poor as described above. If the contact angle is too large, it becomes difficult for the paint to enter the cell grooves, resulting in uneven filling and skipping.

According to a second aspect of the present invention, there is provided a coating method comprising a die having a paint reservoir to which a paint is supplied, wherein a magnetic paint is formed on a continuously running support through a slit provided at the tip of the die. In the coating method of applying while extruding, low friction due to a composite plating film in which fine particles of ethylene tetrafluoride are dispersed in an electroless nickel plating film or an electrolytic nickel-phosphorus film at least at both ends in the width direction of the tip surface of the die. And applying at a coating speed of 200 m / min or more.

In the extrusion method, a wide slit is formed facing the front end surface, and a die having a doctor edge near the front end surface is used. This is a method in which a continuously extruded paint is applied on the support with a uniform thickness by the doctor edge.

In the present invention, at least the both ends in the width direction of the front end surface of the die are subjected to a low friction treatment. Thereby, the coefficient of friction of the tip surface is reduced, and dust is generated from the surface of the support even when the support is continuously run in a state where the surface of the support is in contact with the tip surface. And a stable coating film can be formed.

Since a good lubricating effect is required to be maintained for a long period of time, a surface treatment with a composite plating film containing fine particles having lubricity is suitable as the above-mentioned low friction treatment. The composite plating film containing the fine particles having lubricity is one in which the fine particles having lubricity are uniformly dispersed and co-deposited in the electroless plating film,
For example, a material in which fine particles of ethylene tetrafluoride (trade name, Teflon) are dispersed in an electroless nickel film may be used.

The thickness of the composite plating film is 3 to 30 μm.
m is preferable. The thickness of the composite plating film is 3
If the thickness is smaller than μm, the coefficient of friction of the tip surface of the die cannot be sufficiently reduced, and the generation of dust from the surface of the support cannot be suppressed. Conversely, when the film thickness is more than 30 μm, the support at the portion where the composite plating film is formed is lifted, and the coating film cannot be stably supplied to the surface of the support.

Each of the above-mentioned coating apparatuses is suitable for application of a magnetic paint on a coating type magnetic recording medium. In this case, however, a magnetic powder constituting a non-magnetic support or a magnetic coating film, a resin binder, As the agent and the like, any conventionally known agents can be used, and are not limited at all. To illustrate,
Examples of the nonmagnetic support include polyester resins such as polyethylene terephthalate and polyethylene-2,6-naphthalate, aromatic polyamide films, and polyimide resin films.

Examples of the ferromagnetic powder include ferromagnetic metal materials such as Fe, Co and Ni, and Fe-Co, Fe-Ni and Fe-
Co-Ni, Co-Ni, Fe-Mn-Zn, Fe-N
i-Zn, Fe-Co-Ni-Cr, Fe-Co-Ni
-P, Fe-Co-B, Fe-Co-Cr-B, Fe-
Ferromagnetic metal particles made of various ferromagnetic alloy materials containing Fe, Co, and Ni as main components, such as Co-V, are preferable.

In the above ferromagnetic powder for a magnetic recording medium, Al, Si, Ti, C
Elements such as r, Mn, Cu, Zn, Mg, and P may be added.

Examples of the binder include polymers such as vinyl chloride, vinyl acetate, vinyl alcohol, vinylidene chloride, acrylates, methacrylates, styrene, butadiene, acrylonitrile, and copolymers of two or more of these. Examples thereof include a polyurethane resin, a polyester resin, and an epoxy resin. The ferromagnetic powder is dispersed in these binders to form a magnetic layer.

As the solvent for the magnetic coating material, any of the conventionally known solvents can be used and is not limited at all. Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, methyl acetate, ethyl acetate Butyl ether, butyl acetate, ethyl lactate, ester such as glycol acetate monoethyl ether, glycol dimethyl ether, glycol monoethyl ether, glycol ether such as dioxane, aromatic hydrocarbon such as benzene, toluene, xylene, and fat such as hexane and heptane. Group hydrocarbons, chlorinated hydrocarbons such as methylene chloride, ethylene chloride, carbon tetrachloride, chloroform, ethylene chlorohydrin, and dichlorobenzene.

Further, in addition to the binder and the ferromagnetic powder, a dispersant, a lubricant, an abrasive,
An antistatic agent, a rust inhibitor and the like may be added. Further, a back coat layer, a top coat layer, and the like may be formed on the magnetic recording medium as needed. In this case, the conditions for forming the back coat layer, the top coat layer, and the like are not particularly limited, as long as they are generally applied to a method of manufacturing this type of magnetic recording medium.

The coating apparatus of the present invention can be used not only for applying a magnetic paint but also for applying a back coat layer or a top coat layer in the process of manufacturing such a coating type magnetic recording medium. It is possible.

The coating apparatus which has been subjected to the low friction treatment of the present invention can be used not only for applying a magnetic paint, but also for printing. It is also conceivable to apply a conversion process.

[0029]

The gravure roll surface which has been subjected to the friction reduction treatment of the present invention has a lower surface tension than the surface which has been subjected to the hard chrome treatment, so that the contact angle with water is large (the wetting property is small). I have. Therefore, the paint does not easily adhere to the grooves of the cell pattern, and the transferability to the support is excellent. In particular, even when a paint having high thixotropy is used, no air layer is formed between the cell grooves and the support, and the paint is easily transferred to the support.

When the above-described coating apparatus is used, the transfer of the paint can be performed smoothly and uniformly.
It becomes possible to apply at twice or more speed. Further, the pressure of the backup roll for pressing the paint to the support can be reduced, and the nip width is reduced, so that the contact resistance with the support is reduced and the wear resistance of the gravure roll is improved.

In the extrusion-type coating apparatus, the friction coefficient of the front end surface is reduced by applying a low friction treatment to at least both widthwise ends of the front end surface of the die for supplying the coating material onto the support. . For this reason, even if the support is run in a state in which the support is in contact with the front end surface, the slidability is good, and the generation of dust from the surface of the support due to wear is reduced.

Further, by using a surface treatment with a composite plating film containing fine particles having lubricating properties, the lubricating properties can be imparted to the tip end surface, and the effect can be improved. For a long time.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below in detail with reference to the drawings. <Experiment 1> First, using the guarian roll of the present invention,
The case where a magnetic paint is applied to a non-magnetic support will be described.

FIG. 7 shows a coating apparatus which is a direct gravure roll. The coating device 31 includes a gravure roll 32 having a cell pattern engraved on its surface, a doctor blade 34 for measuring the magnetic paint 33 picked up by the gravure roll 32, and a non-magnetic support for the gravure roll 32. Backup roll 35 for crimping
Consisting of

In the application by such an apparatus, the magnetic paint is picked up by the cell pattern of the gravure roll 32, and the magnetic paint limited to a certain amount is adhered on the non-magnetic support 36 by the doctor blade 34. The magnetic paint is continuously and uniformly applied by rotating the gravure roll 32 and the backup roll 35.

The magnetic paint transferred onto the non-magnetic support is applied to the unevenness of the cell pattern of the gravure roll 32, but is smoothed by the smoothing 38.

On the other hand, the non-magnetic support 36, which moves and runs from the unwinding side to the winding side, is supported and guided by the guide rolls 37, and is appropriately tensioned by the guide rolls 37 and the like. , So that smooth running can be performed.

The above is the basic configuration of this coating apparatus. In this coating apparatus, the gravure roll 32
The surface of the gravure roll 32 will be described in detail below. As shown in FIGS.
Helical annular convex portions are formed on the two surfaces as multi-start screws.

FIG. 10 is an enlarged cross section taken along line AA 'in FIG. Numeral 40 denotes a plating film, which is formed on the soft material STKM steel 39 after patterning.

Then, a coating film of a magnetic material is formed on a non-magnetic support by a coating apparatus in which the type of the surface treatment of the gravure roll is changed as follows, and various magnetic tapes using this as a magnetic layer are manufactured. did.

Types of surface treatments Example 1: Formation of composite plating film in which fine particles of ethylene tetrafluoride resin are dispersed in electroless nickel film Example 2: Ethylene tetrafluoride resin in electric field nickel-phosphorus film Formation of composite plating film in which fine particles are dispersed Comparative Example 1: Hard chrome treatment Comparative Example 2: Formation of Ti-N (nitride film) Comparative Example 3: Thermal spraying of tetrafluoroethylene resin

Here, the characteristics of the composite plating films shown in Examples 1 and 2 are mainly in excellent release properties and high hardness. Further, by performing an appropriate heat treatment, the ethylene tetrafluoride resin is dissolved on the surface of the film to form a thin film, so that the releasability is further improved. In addition, nickel
In a composite plating film in which fine particles of a tetrafluoroethylene resin are dispersed in a phosphorus film, the hardness is also increased by this heat treatment. Therefore, by combining these composite plating films with heat treatment, higher performance films can be obtained.
Was subjected to a heat treatment.

The fine particles of the ethylene tetrafluoride resin used had a diameter of about 0.15 to 0.2 μm. The maximum possible thickness of the composite plating film is 10
μm, and the hardness was 500 to 900 which is close to hard chrome in Vickers (HV) hardness. The content of the tetrafluoroethylene resin in the coating is 7 to 10% by weight in Example 1, and 6 to 7% by weight in Example 2.

When applying a magnetic paint using a gravure roll having been subjected to the above-mentioned surface treatment, polyethylene terephthalate was used as the nonmagnetic support, and the following materials were used as the magnetic paint. Magnetic powder: Co-coated γ-Fe ₂ O ₃ binder: Vinyl chloride copolymer polyurethane resin Solvent: methyl ethyl ketone, cyclohexanone, toluene Additive: lecithin

The magnetic paint has a solid content of 40%, 5% or less.
The gravure roll having a viscosity of 800 cps and various surface treatments was applied to a non-magnetic support.

Then, the contact angle of the gravure roll surface with water, the transfer state of the magnetic paint, and the abrasion resistance of each coating apparatus were examined. Table 1 shows the results. Table 1
In the evaluation of the transfer state, the mark ○ indicates that the transfer state is good, the mark X indicates that there is skipping and uneven coating,
The symbol Δ indicates that the smoothing can be performed by smoothing.

[0047]

[Table 1]

The abrasion resistance was evaluated based on the displacement difference (indicated by w in FIG. 9) of the helical ridge width of the gravure roll after coating on a nonmagnetic support of 10,000 m. The contact angle is a product name of Elma Co., Ltd.
G-1 (13-100-0) was measured by a contact angle measuring instrument.

As shown in Table 1, as in the present embodiment, a composite plating film in which fine particles of ethylene tetrafluoride were uniformly dispersed in an electroless nickel film as a low friction treatment on the gravure roll surface and co-deposited was used. In the case of forming, or in the case of forming a composite plating film in which fine particles of ethylene tetrafluoride are uniformly dispersed in nickel or nickel phosphorus in an electric field and co-deposited, coating is performed even at a high coating speed of 200 m / min or more. Stable coating film formation without unevenness could be performed. This indicates that by forming the composite plating film as described above, a coating device having excellent transferability of the magnetic paint from the gravure roll to the non-magnetic support was obtained.

Further, it can be seen that the gravure roll has excellent wear resistance.

On the other hand, when a hard chrome plating treatment is simply applied, when a nitride coating is provided, or when a tetrafluoroethylene resin is sprayed, etc., a high-viscosity magnetic paint is applied to prevent uneven coating. A poor transfer state cannot be obtained, and the amount of wear on the gravure roll surface is large.

When a gravure roll having a small contact angle and subjected to hard chrome plating or a gravure roll provided with a nitride film is used, the magnetic paint having a high thixotropy is transferred from the cell grooves of the gravure roll to a non-magnetic support. In some cases, the magnetic layer becomes thin and the coating becomes uneven even if the surface is smoothed by smoothing. Further, in order to transfer the magnetic paint to a non-magnetic support, it is necessary to apply pressure with a large force, and the amount of wear on the surface of the gravure roll increases.

When a gravure roll sprayed with a tetrafluoroethylene resin having an excessively large contact angle is used, the magnetic paint cannot enter the cell grooves, and the magnetic paint cannot be adhered to the nonmagnetic support.

Therefore, in order to obtain a good coating state, it is necessary to use an electric field or electroless nickel coating or the like containing fine particles having lubricity such as fine particles of ethylene tetrafluoride having a contact angle of about 45 °. It has been found that a plated film is preferred.

<Experiment 2> Next, a method of applying a magnetic paint to a non-magnetic support using the extrusion type coating apparatus of the present invention will be described.

In this coating apparatus, as shown in FIG. 1, a substantially rectangular parallelepiped metal having a predetermined width is provided in the middle where the non-magnetic support 6 is sequentially run from the unwinding side to the winding side. A die (extruder) 4 composed of blocks is provided. The die 4 is disposed on the side of the non-magnetic support 6 running downward from above in the figure, and is disposed such that the tip end surface 4a of the die 4 faces the surface of the non-magnetic support 6. Is established.

As shown in FIG. 3, this die 4 has a so-called wedge shape in which the vicinity of the tip surface 4a is cut off obliquely in a straight line, and the tip surface 4a is formed of a cemented carbide or the like. Has been The die 4 has a slit 5 facing the front end face 4a and having a width corresponding to the coating width. The slit 5 is a gap through which the coating material 1 made of a magnetic material is extruded, and is usually a very narrow gap of about 0.01 to 2.0 mm.

On the back side of the slit 5, a pocket (coating liquid reservoir) 3 communicating with the slit 5 is formed. The pocket 3 has a length substantially equal to the width of the slit 5 and is formed as an orifice-shaped space. At both ends of the pocket 3, coating liquid supply ports (not shown) are provided so as to open at both end faces of the die 4. Coating liquid supply pipes for introducing the paint 1 are provided at these coating liquid supply ports. 9
Is connected. A pump 2 is attached to the middle of the coating liquid supply pipe 9 so that the paint 2 is pumped from the coating liquid supply pipe 9 into the pocket 3 by a predetermined pressure. Has been made. Therefore, the pocket 3 serves as a space for receiving the paint 1 to be fed under pressure, and has a function of an accumulator.

The paint 1 fed into the pocket 3 is
It is supplied into the slit 5 and is further extruded onto the surface of the non-magnetic support 6 running from the tip of the slit 5 to form a coating film 7. On the other hand, the non-magnetic support 6 moving and running from the unwinding side to the winding side
Are supported and run by the guide rolls 10a, 10b, and the guide rolls 10a, 1
0b is applied with an appropriate tension so that smooth running can be performed.

Therefore, in this coating apparatus, as shown in FIG. 2, the tip surface of the die 4 is fed to the surface of the non-magnetic support 6 which is fed from the unwinding side and travels in the direction of arrow A in FIG. The magnetic material is extruded from a slit 5 formed on the abutting surface toward the distal end surface 4a to form a coating film 7. At this time, the slit 5
By regulating the width, to limit the coating width W ₂ of the coating film 7 formed on the non-magnetic support body 6 having a width W _1,
The uncoated portion 8 is formed to have a width of about 3 to 10 mm at both ends in the width direction of the nonmagnetic support 6. As a result, the extruded magnetic material is transferred to the non-magnetic support 6.
Of the film on the back side of the film, and a good coating film can be formed.

The above is the basic configuration of the coating device. In this coating device, the tip surface 4a of the die 4 is used.
Is characterized in that both ends in the width direction are subjected to a low friction treatment. Hereinafter, the configuration of the tip end surface 4a of the die 4 will be described in detail. On the tip surface 4a of the die 4,
As shown in FIG. 4, a slit 5 is formed in a substantially central portion of the distal end face 4a in an opening shape. Spacers 12, 12 are arranged on both ends in the width direction of the slit 5, and the application width W _{2 of the} magnetic material extruded from the slit 5 is regulated by the spacers 12, 12.

On the outer side of the slit 5 on the front end face 4a, that is, at both ends in the width direction of the front end face 4a (shaded areas in the figure), tetrafluoride is added to the electroless nickel coating as a low friction treatment. A composite plating film 11 in which ethylene fine particles are uniformly dispersed and codeposited is formed. The region where the composite plating film 11 is formed is a portion which is directly in contact with the above-mentioned non-coated portion (not shown) of the non-magnetic support, and by applying a friction reducing treatment to this portion, The coefficient of friction on the surface of the non-magnetic support is reduced, and good slidability is obtained. As a result, generation of dust from the surface of the non-magnetic support due to contact between the tip surface 4a and the surface of the non-magnetic support, damage to the tip surface 4a, and the like are prevented, and a stable coating film can be formed. Becomes

It is sufficient that the composite plating film 11 is formed at least at both ends in the width direction of the front end face 4a as in the present embodiment. For example, as shown in FIG. There is no problem even if it is formed over the entire area in the width direction.

Therefore, using a coating apparatus having such a configuration, the type of the above-mentioned friction reducing treatment is changed (hereinafter, shown as Examples 3 and 4 and Comparative Examples 4 to 9) on a non-magnetic support. Various magnetic tapes were produced by forming a coating film of a magnetic material thereon and using the coating film as a magnetic layer. The material of the die was selected from one of stainless steel, cemented carbide, and carbon tool steel. In addition, as a nonmagnetic support, 14 μm
A thick polyester film was used, and the running speed of the non-magnetic support was set such that the speed when the non-magnetic support was simply run without coating was 300 m / min.

With respect to the obtained magnetic tape, the state of generation of dust from the surface of the non-magnetic support and the presence or absence of scratches on the tip surface of the die were examined. Table 2 shows the results. In Table 2, in each of the evaluation items, a circle indicates a state in which dust from the non-magnetic support was not generated, or a state in which no scratch was generated on a tip surface of the die, and a cross indicates the dust or the dust. It shows a state in which a large amount of scratches have occurred on the tip end surface, and a triangle mark shows a state in which the tip end surface has been slightly scratched.

[0066]

[Table 2]

As shown in Table 2, when forming a coating film on the non-magnetic support as in the present embodiment, the die of the die directly contacting the uncoated portion of the running non-magnetic support was used. In the case of forming a composite plating film in which fine particles of ethylene tetrafluoride are uniformly dispersed in an electroless nickel film as low friction treatment on both ends in the width direction of the tip surface, There was no generation of dust from the surface of the non-magnetic support and no damage to the tip surface, and the coating film could be formed stably. This is because an excellent lubricating effect was obtained and the effect could be maintained for a long time by forming the composite plating film as described above on both ends in the width direction of the tip surface of the die.

On the other hand, when chromium plating is simply applied to both ends in the width direction of the tip surface of the die, or when fine particles having lubricity are retained, dust from the surface of the non-magnetic support is reduced. It was not possible to prevent the above-mentioned damage to the front end surface while suppressing the occurrence, and a good effect was not obtained.
Therefore, in order to prevent adverse effects due to contact with the non-magnetic support, a composite plating film treatment with an electroless nickel film or the like containing fine particles having lubricity such as fine particles of ethylene tetrafluoride is preferable. It turns out.

[0069]

As is clear from the above description, the surface of the gravure roll subjected to the low friction treatment of the present invention has a large contact angle with water (small wetting property), so that the cell pattern of the gravure roll is small. The coating device hardly adheres the paint to the groove and has excellent transferability to the support.

When the coating apparatus of the present invention is used, the coating can be transferred smoothly and uniformly, so that the coating can be performed at twice or more the speed of the conventional method, and high productivity can be obtained. Furthermore, since the transferability of the paint is good and there is no need to apply a large pressure to the backup roll to press it against the support,
Excellent gravure roll wear resistance.

Further, in the extrusion type coating apparatus of the present invention, when forming a coating film on the support, a low-friction treatment is applied to the tip end surface of the die which makes direct contact with the running support surface. As a result, good slidability can be ensured, and generation of dust from the surface of the support and damage to the end surface can be eliminated. For this reason, the coating material can be stably applied to the surface of the support, and the accuracy deterioration of the slit provided in the die is reduced. Therefore, the coating film obtained is of high quality with remarkably improved properties such as durability.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing a configuration of a coating apparatus used in a process of forming a magnetic layer to which the present invention is applied.

FIG. 2 is an enlarged plan view of a main part showing a state in which a running support and a tip end surface of a die are in contact with each other.

FIG. 3 is an enlarged sectional view of a main part showing a configuration near a tip end surface of a die.

FIG. 4 is an enlarged front view of a main part showing a configuration of a tip surface of a die.

FIG. 5 is a cross-sectional view showing a state in which a low friction treatment is applied to the entire area in the width direction of the tip surface of the die.

FIG. 6 is a cross-sectional view showing a state in which a tip end surface of a conventional die and a running support are in contact with each other.

FIG. 7 is a schematic view showing a configuration of a coating apparatus used in a process of forming a magnetic layer to which the present invention is applied.

FIG. 8 is a perspective view showing an example of a cell pattern of a gravure roll.

FIG. 9 is a front view of the gravure roll of FIG.

FIG. 10 is an enlarged sectional view of the surface of a gravure roll.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Paint 3 ... Pocket 4 ... Die 5 ... Slit 6 ... Non-magnetic support 7 ... Coating film 8 ... Uncoated part 11 ... Low friction processing Area to be made 32 ... Gravure roll 33 ... Paint 34 ... Doctor blade 35 ... Backup roll 36 ... Non-magnetic support 40 ... Coating plating

Continuation of the front page (56) References JP-A-2-292042 (JP, A) JP-A-4-48956 (JP, A) JP-A-3-76874 (JP, A) JP-A-54-101978 (JP) JP-A-3-4966 (JP, A) JP-A-5-261330 (JP, A) JP-A-1-290776 (JP, A) JP-A-4-271016 (JP, A) 3-41618 (JP, A) JP-A 2-142667 (JP, U) JP 2-43255 (JP, B2) JP 3-19605 (JP, B2) JP 60-48599 (JP, B2) B2) US Patent 5,516,545 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B05C 1/08-1/12 B05C 5/02 B05D 1/26 B05D 1/28 G11B 5/842

Claims (2)

(57) [Claims] 1. A magnetic coating supplied to a gravure roll surface.
Coating method in which the coating is continuously transferred onto the support
The gravure roll surface by electroless nickel plating
Or ethylene tetrafluoride in electrolytic nickel-phosphorus coating
Low friction treatment by composite plating film with fine particles dispersed
With a viscosity of 5,000 to 10,000 cps using a B-type viscometer.
A gravure roll that has undergone a low friction treatment
Coating method, wherein the coating is performed using a tool. 2. A paint reservoir for supplying a paint.
Die tip on a continuously running support with a die
While extruding magnetic paint through the slits
In a coating method of applying a cloth , an electroless two-dimensional
In nickel plating or electrolytic nickel-phosphorus coating
Plating film with fine particles of ethylene tetrafluoride dispersed in
A low-friction treatment, and apply at a coating speed of 200 m / min or more.
Coating method.